[changelog] setting relase date in changelog.

Author: truthbk

CHANGELOG.md

@@ -1,7 +1,7 @@
 Changes
 =======
 
-# 1.9.0 / Unreleased
+# 1.9.0 / 2016-12-20
 
 ### Notes
 
@@ -306,4 +306,4 @@ Changes
 [@scottgeary]: https://github.com/scottgeary
 [@sethcleveland]: https://github.com/sethcleveland
 [@swwolf]: https://github.com/swwolf
-[@tuxinaut]: https://github.com/tuxinaut
+[@tuxinaut]: https://github.com/tuxinaut